Semantic Web service discovery: state-of-the-art and research challenges

Ubiquitous computing paradigms involving social agents require principled selection of services, context-aware analysis, and satisfaction of requests, as well as dynamic interaction and negotiation with other agents. Synergies between semantic technologies and service discovery facilitate rich and formal representations of services and agent interactions as well as specialization and generalization of service needs. In this paper, we provide an extensive review of semantic Web service discovery, highlighting the state-of-the-art approaches, the key semantic formalisms employed, as well as benchmarks and testbeds for performance evaluation. Defining a generic framework for semantic service discovery, we describe the key tasks and criteria involved in agent-based computing. A detailed comparison of the popular discovery systems is performed with a discussion on trade-offs between existing approaches. We conclude by pointing out important research challenges to be addressed for next-generation service discovery by dynamic multi-agent systems in complex environments.     

Bounded Budget Connection (BBC) games or how to make friends and influence people,on a budget

Motivated by applications in social and peer-to-peer networks, we introduce the Bounded Budget Connection (BBC) game and study its pure Nash equilibria. We have a collection of n   players, each with a budget for purchasing links. Each link has a cost and a length. Each node has a preference weight for each node, and its objective is to purchase outgoing links within its budget to minimize its sum of preference-weighted distances to the nodes. We show that determining if a BBC game has pure Nash equilibria is NP-hard. We study (n,k)$(n,k)$-uniform BBC games, where all link costs, lengths, and preferences are equal and every budget equals k  . We show that pure Nash equilibria exist for all (n,k)$(n,k)$-uniform BBC games and all equilibria are essentially fair. We construct a family of equilibria spanning the spectrum from minimum to maximum social cost. We also analyze best-response walks and alternative node objectives.     

Approximation Algorithms for Multiprocessor Scheduling under Uncertainty

Motivated by applications in grid computing and project management, we study multiprocessor scheduling in scenarios where there is uncertainty in the successful execution of jobs when assigned to processors. We consider the problem of multiprocessor scheduling under uncertainty, in which we are given n unit-time jobs and m machines, a directed acyclic graph C giving the dependencies among the jobs, and for every job j and machine i, the probability p _ij of the successful completion of job j when scheduled on machine i in any given particular step. The goal of the problem is to find a schedule that minimizes the expected makespan, that is, the expected time at which all of the jobs are completed.     

The effect of demand elasticity on security prices for the PoolCoand multi-lateral contract models

Optimum power flows and security constrained power flows assume that customer demand is a fixed quantity. In the new competitive environment, it is necessary to assume that demand is elastic and will vary as a function of price. A critical element in any competitive model, whether it be a PoolCo or a multi-lateral contract model, is for a system operator to ensure reliability and feasibility of the power system operating point. Security pricing for feasibility was first advanced by Schweppe et al for the case of line flow constraints for a PoolCo model. Using geometry, this paper generalizes the approach to include any security constraint for a general competitive model. The paper discusses interpretations of security pricing and its possible implementation in energy management systems     

New method of calculating calorific values from elemental compositions of fossil fuels

A new method of calculating the calorific values of fossil fuels from their chemical composition has been developed, based on the concept that heats of reaction of stoichiometric fuel-oxidizer systems are rectilinearly related with the total oxidizing or reducing valancies of the mixture. The calorific value of fossil fuels has been shown to be directly related to the net reducing valencies of the fuel. The proposed method is simple and compares favourably with the other prominent methods reported in the literature.     

Glutamine deprivation induces apoptosis in intestinal epithelial cells

BACKGROUND: Glutamine is the most abundant amino acid in the blood, and its deprivation leads to gut mucosal atrophy. The small intestinal mucosa is maintained by a balance between cell proliferation and cell death by apoptosis. We reported that glutamine is required for nitrogen-stimulated proliferation in intestinal epithelial cells. We do not know whether glutamine regulates apoptosis in the gut. The purpose of this study is to determine whether glutamine deprivation induces apoptosis in rat intestinal epithelial (RIE-1) cells and to compare the effect of glutamine starvation with that of methionine and cysteine (Met/Cys) starvation. METHODS: RIE-1 cells were deprived of either glutamine or Met/Cys for 24 hours. Cell numbers were determined by cell counting and tetrazolium enzymatic assay. Apoptosis was quantified by Annexin V assay and confirmed by DNA gel electrophoresis and Hoecsht nuclear staining. RESULTS: Deprivation of glutamine or Met/Cys resulted in decreased cell numbers. However, only the glutamine-deprived group showed significant induction of apoptosis with increased Annexin V staining, DNA laddering, and nuclear condensation. CONCLUSIONS: This study provides biochemical and morphologic evidence that glutamine deprivation induces apoptosis in rat intestinal epithelial cells. In contrast, Met/Cys starvation suppresses cell number without induction of apoptosis. These results suggest that glutamine serves as a specific survival factor in enterocytes.